The invention of this application relates to method and apparatus for measuring microdistances (distances that are typically from 0.1 up to about 300 microns or more) between first and second objects with high accuracy.
For example, in the manufacture of fiber optic systems, it is desirable to bring a single mode or multimode fiber optic member into close relation (typically 2 to 20 microns) with a laser diode chip without scratching the chip, typically as part of a pigtailing operation. Then, the closely spaced fiber optic member may be oriented with the laser diode chip to a position where maximum light from the laser diode chip passes through the fiber optic member, and the laser diode chip and fiber optic member are secured together by a laser welding or other means in that position.
It is distinctly undesirable in such a process to allow the end of the fiber optic member to touch the laser diode chip, since damage can take place if that happens. Accordingly, there is needed a means to reliably move the two members into closely spaced relation of as little as one or two microns, without causing them to touch. By this invention a system for accomplishing the above is provided, with the processing being reliable, of low cost, and suitable for use in the manufacture of commercial quantities of laser diode chips having bonded fiber optic members.
Additionally, the process of this invention may be used for other purposes as well, where it is desired to bring two objects into extremely close proximity while preventing them entering into actual contact with each other.